Method and apparatus for the manufacture of litharge



ct 2l, 1930. E, KNAPP ET ALv 1,779,003

METHOD AND APPARATUS FOR THEMANUFAGTURE 0F LITHARGE Filed May 5?' 1925`2 sheets-sheet 1 lNvENToRs e www Oct. 21, 1930. E, KNAPP T AL 'l1,779,003

METHOD ANDl APPARATUS FOR THE MANUFACTURE 0F LITHARGE Filed 'May 5, 19252 Sheets-Sheet 2 'ArroRNEYs' A Panarea oca. 2i., 193e .EDGARHKNAPP ANDCARL G. ALLGRUNN, F MIDDLEPORT, NEW YORK, ASSIGNORSTO TN'IAGARA SPRAYERCOMPANY, 0F MIDDLEPOlB/T, NEW YORK,`A CORPORATION'OF ra-tus withportions broken away; land .throughout the body of liquid and thenskimlitharge.

NEW YORK f METHOD AND APPARATUS FOR THE MANUFACTURE 0F lLIT'HARGIE Thisinvention relates to a method and =ap' paratus for the manufacture oflitharge.

A n object of the invention is to provide asimple method for themanufacture of Another object concerns the provision of simpleandeliicient means whereby the improved method can be applied,

The invention is illustrated in the 'drawin o f whichv igure l is a sideelevation of the appa Figure 2'is an end elevation thereof. The form ofthe invention shown in the `drawings is a preferredform, although it ismethod includes a-new step in the formation of litharge from lead whichcomprises foreing air into the molten lead at various points ming olfthe litharge which forms at'the top surface of the liquid. We. believeit to be new to form litharge on the surface of a body of molten leachby'v forcing airl through the body of liquid Wealso believe it to be newto combine with this apparatus a machine for skimming off the lithargeas soon as it is formed. We also believe it to be new to com bine withthe above-mentioned apparatus an apparatus for carrying the 'lithargefrom .the initial pan te a furnace where it is finished.

The preferred form of the invention is shown in the drawings, which alsoillustrate the new method employed. In this apparatus, developed to ap1y the method of making litharge above re erred to, we employ a .may besuitably forced into the bottom of melting pan 10, shown in dotted linesin both of the figures. vThis pan; along its bottom' and in any.suitable jdetail manner (not shown) is provided with a series of holesconnected to pipes such as 11 wherebyair the liquid .and .up through thebody'of liquid 'at the same time that the oil or. gas burners 1925.Serial N0. 28,271.

l2 are heating the pan. A suitable hood 13.

placed over the pan. Within the hood is disposed a plurality of.skiln'n'iers such as 14 across the surface of the liquid in the pan l0-to skim the litharge floating on the surface,

in the forni of plates connectedinany dei upl an incline l5 where theliquid lead can drain and return to the pany .andthe litharge is carried-up to drop .down an inclinedplate -16 into a trough 1T havingrv a screwconveyor moving the litharge -to one end, where it drops into a trough18 colitaining a screw conveyonll). This conveys the litharge to a pointwhere it is carriedl up by 'elevator buckets 2O to a hopper 2l. Fromthis hopper'it ber has bottom doors 2 4 which can be opened to allow acharge of finished litharge to drop out into a pit :25 where i't-can becooledL yAn air-pump 26 is connected to a pipe 27 leading to thefinishing chamber, and by a pipe 28. to the air chutes below the pan 10and to the hood 13 abovethe pan.

drops down through achute22 into a finish- 111g furnace chamber'23. Thisfurnace cham- It will be obvious, therefore that in the operation of thedevice the pan of molten lead -is heated preferably to about 550 C.,during which time air is being forced .upward through the bottom of thepanA and through the lead at various points by means f. the. pluralityof pipes distributed over the whole bottom surface-of the pan. Theaction of the air on the lead causes a formation of partially formedlitharge which floats on the sur` face ofI the liquid. This .formationisrel i moved by means of the skimmers attached to the endless chain.skimmer is continuous, carrying off the'product as fast as it is formed.At the end of the sulicient'lengtlrto-`a11ow the excess lead'to drainback into the pan. At the -top of the incline't falls onan apronand`slides into a This operation of the I trough, unless it is' removedby means of a screw conveyorv to abucket elevator carrying it up intothe hopper arranged above and near the finishing-furnace.

E the hopper it i's fed into the finish-l ing furnace and heated toabout 600 C. This furnace is provided with a shaft 29 carrying two ormore arms such as 30 and 31 acting. as agitator arms. driven by anysuitable means, such as gearing, at a speed of about two R. P. M. Theseagitator-s keep the mass in constant agitation '[or about three or four'hours. It is then taken out of the furnace by opening the bot tonidoors. After it is cooled in the pit it is taken out and ground.

lVhat we claim is':-

l. Y method ol manufacturing litliarge from metallic lead, 'whichcomprises melting v lead, forcing air up through the molten lead topartiall \v torni litliarge, then continuously skimming oit' thelithaige floating on the top ot' the liquid as t'ast as it is formed.and then conveying the litlial-ge tliusc'ollected to a iinishing furnaceand subjecting it in said fur,-

nace to stirring, in intimate contact with gaseous oxygen. Y

2. A method of iiianuiacturing litliarge from metallic lead, whichcomprises melting the lead, forcing air up through the molten lead topartially forni lithargc` then continuously skimming off the lithargefloating on the top of the liquid as fast `as it is formed, draining oftthe excess-of vmolten lead from the partially formed litliarge, and thenconveying the litharge thuscollected to a finishing turnaceandsubjecting it in said furnace to stirring, in intimate Contact withgaseous 3. A method of manufacturing litharge from metallic lead, Whichcomprises ymelting the lead, forcing air up through the molten lead topartially form litliarge, then coiitiiiuousljyv skimming oli' thelitharge floating on lthe top ot'the liquid as fast as it is Jformed,and then conveying the litliarge thus collectedv to a finishing furnaceand subjecting it in said furnace to stirring.v in intimate contact with.gaseous oxygen at a temperature higherthan that of the molten lead.

4. A method, of vmanufactiiring litharge from metallic lead, whichcomprises melting the lead. maintaining the melted lead at a'temperature of about'() degrees C., forcing air up through; the moltenlead to partially. foi-in lithai-ge, then continuously skimming ot thelitharge floating on the top of the liquid as fast as it is formed, andthen conveying the litharge thus collected to atinishingfurnace andmaintaining it in said finishing furnace ata temperature of about GOOdegrees C., while stirring in intimate Contact with air.

EDGAR KNPP. CARL G. ALLGRUNN.

T hese arms are y

